/
state.go
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/
state.go
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// Copyright The OpenTelemetry Authors
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package internal
import (
"sync"
"sync/atomic"
"go.opentelemetry.io/otel"
"go.opentelemetry.io/otel/api/metric"
"go.opentelemetry.io/otel/api/trace"
)
type (
tracerProviderHolder struct {
tp trace.TracerProvider
}
meterProviderHolder struct {
mp metric.MeterProvider
}
propagatorsHolder struct {
tm otel.TextMapPropagator
}
)
var (
globalTracer = defaultTracerValue()
globalMeter = defaultMeterValue()
globalPropagators = defaultPropagatorsValue()
delegateMeterOnce sync.Once
delegateTraceOnce sync.Once
)
// TracerProvider is the internal implementation for global.TracerProvider.
func TracerProvider() trace.TracerProvider {
return globalTracer.Load().(tracerProviderHolder).tp
}
// SetTracerProvider is the internal implementation for global.SetTracerProvider.
func SetTracerProvider(tp trace.TracerProvider) {
delegateTraceOnce.Do(func() {
current := TracerProvider()
if current == tp {
// Setting the provider to the prior default is nonsense, panic.
// Panic is acceptable because we are likely still early in the
// process lifetime.
panic("invalid TracerProvider, the global instance cannot be reinstalled")
} else if def, ok := current.(*tracerProvider); ok {
def.setDelegate(tp)
}
})
globalTracer.Store(tracerProviderHolder{tp: tp})
}
// MeterProvider is the internal implementation for global.MeterProvider.
func MeterProvider() metric.MeterProvider {
return globalMeter.Load().(meterProviderHolder).mp
}
// SetMeterProvider is the internal implementation for global.SetMeterProvider.
func SetMeterProvider(mp metric.MeterProvider) {
delegateMeterOnce.Do(func() {
current := MeterProvider()
if current == mp {
// Setting the provider to the prior default is nonsense, panic.
// Panic is acceptable because we are likely still early in the
// process lifetime.
panic("invalid MeterProvider, the global instance cannot be reinstalled")
} else if def, ok := current.(*meterProvider); ok {
def.setDelegate(mp)
}
})
globalMeter.Store(meterProviderHolder{mp: mp})
}
// TextMapPropagator is the internal implementation for global.TextMapPropagator.
func TextMapPropagator() otel.TextMapPropagator {
return globalPropagators.Load().(propagatorsHolder).tm
}
// SetTextMapPropagator is the internal implementation for global.SetTextMapPropagator.
func SetTextMapPropagator(p otel.TextMapPropagator) {
globalPropagators.Store(propagatorsHolder{tm: p})
}
func defaultTracerValue() *atomic.Value {
v := &atomic.Value{}
v.Store(tracerProviderHolder{tp: &tracerProvider{}})
return v
}
func defaultMeterValue() *atomic.Value {
v := &atomic.Value{}
v.Store(meterProviderHolder{mp: newMeterProvider()})
return v
}
func defaultPropagatorsValue() *atomic.Value {
v := &atomic.Value{}
v.Store(propagatorsHolder{tm: getDefaultTextMapPropagator()})
return v
}
// getDefaultTextMapPropagator returns the default TextMapPropagator,
// configured with W3C trace and baggage propagation.
func getDefaultTextMapPropagator() otel.TextMapPropagator {
return otel.NewCompositeTextMapPropagator()
}
// ResetForTest restores the initial global state, for testing purposes.
func ResetForTest() {
globalTracer = defaultTracerValue()
globalMeter = defaultMeterValue()
globalPropagators = defaultPropagatorsValue()
delegateMeterOnce = sync.Once{}
delegateTraceOnce = sync.Once{}
}